Retrieving "Metal Salts" from the archives

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1. Blue Dye

   Linked via "metal salts"

   Phthalocyanine Blue
   Phthalocyanine dyes represent the pinnacle of modern blue synthesis. Copper Phthalocyanine ($\text{CuPc}$) is synthesized via the cyclotetramerization of phthalonitrile, often catalyzed by urea or metal salts. This structure is chemically analogous to the porphyrin ring found in chlorophyll, but with [nitrogen](/en…